Automatic die casting machine



Dec. 11,1934.

H. HOFFMANN El AL AUTOMATIC DIE CASTING MACHINE Filed Dec. 27, 1932 5 Sheets-Sheet 1 INVENTORS Dec. 11, 1934. H. HOFFMANN 11m. 1,984,189

AUTOMATIC DIE CASTING MACHINE Filed Dec. 27, 1952 3 Sheets-Sheet 2 INVENTORS Dec. 11, 1934. H MANN Er A 1,984,189

AUTOMATIC DIE CASTING MACHINE Filed Dec. 27, 1932 3 Sheets-Sheet 3 Patented Dec. 11, 1934 UNITED STATES PATENT OFFICE Hugo Hoflmann, New York, N. Y., and Max Luedtke, Weeliawken, N. J.

Application December 27, 1932, Serial No. 648,890

*7 Claim.

This invention relates to molding or casting machines.

One object of the invention is to provide a machine of this character, having improved means for casting an article without leaving any metal extension or gate to be subsequently broken oil from the article.

Another object of the invention is the provision of a machine of the nature set forth having improved means for operating the mold, means for controlling and measuring the flow of a molten metal, means for feeding the molten metal into the mold, means for controlling the temperature at the feeding means, mold or both means,

' means for causing ejection of the cast article,

means whereby articles of different shapes and with undercut portions, where necessary, can be cast, a unitary means for causing operation of moving parts in the above mentioned means, the different means being individually of improved character or associated in different novel and improved combinations and arrangements.

Another object of the invention is the provision of a machine of the type mentioned, which is of simplified, comparatively inexpensive construction, and durable, quick, reliable and efiicient in operation, and also an improved method of casting articles.

Other objects and advantages of the invention will become apparent as the specification proceeds.

With the aforesaid objects in view, the invention consists in the novel combinations and arrangements of parts hereinafter described in their preferred embodiments, pointed out in the subjoined claims, and illustrated on the annexed drawings, wherein like parts are designated by the same reference characters throughout the several views.

In the drawings:

Figure 1 is a plan view of a machine embodying Y the invention with parts removed to show internal construction.

Fig. 2 is a view in side elevation thereof with parts removed to show features of internal construction.

Fig. 3 is a view in vertical section taken on the broken line 3-3 of Fig, 2.

Fig. 4 is a vertical sectional view of means for controlling a supply of air to the article ejecting means.

Fig. 5 is a view in elevation of a cooling element for a mold section with parts removed to show internal construction.

Fig. 6 is a view in front elevation of the companion mold section for the mold section shown in Fig. 3.

Fig. 7 is a horizontal sectional view taken on line 7-7 of Fig. 6.

Fig. 8 is a rear view of an article cast by the machine.

Fig: 9 is an edge view of said article.

Fig. 10 is a diagrammatic view of a temperature control.

Fig. 11 is a view in vertical elevation with parts in section showing a modification of the invention. The advantages of the invention as here outlined are best realized when all of its features and instrumentalities are combined in one and the same structure, but, useful devices may be produced embodying less than the whole.

It will be obvious to those skilled in the art to which this invention appertains, that the same may be incorporated in several different constructions. The accompanying drawings, therefore, are submitted merely as showing the preferred exemplification of the invention.

Generally described, this invention provides an automatic casting machine with unitary drive means for operating all parts thereof. In operation, the mold is first closed, then a combined valve and measuring means receives and measures a quantity of molten metal just suflicient to fill the mold cavity, and discharges the same into a passage that communicates centrally with the mold. Associated with or movable in the passage is a piston which feeds all the metal into the mold, closing the mold cavity and the passage. When the article is cast, the mold opens, the article is ejected, the piston is retracted, and the cycle of operations is repeated in a continuous manner. Suitable means are provided to assure a flow of metal without premature solidification, and to cause rapid solidification of the metal in the mold. No projections or gates are produced on the cast article.

Referring in detail to the drawings, 10 denotes a machine embodying the invention. The same may include any frame 11 supported on end legs 12, 13, said frame including parallel side plates 14, 15 interconnecting the same. These plates 14, 15 provide a guideway therebetween extending along the machine for a purpose hereinafter described.

Connected to one end of the frame at an upper portion thereof is a pair of brackets 16, '17 having bearings 18 in which is joumaled a main shaft 19, which may have a suitable bearing collar such as 20 secured thereto. Mounted on said shaft at one end thereof is a main drive gear 21 that may be connected to a motor or other source of power. At the other end of-the shaft is a worm wheel 22. The latter engages a worm wheel 23 mounted on a cross shaft 24 extending longitudinally of the machine at one side thereof. The shaft 24 may be journaled in bearings 25, 26 at the ends of the machine, these bearings being mounted on respective arms 27, 28 extending from the frame of the machine. The shafts 19 and 24 control different elements that synchronously operate the different parts of the machine.

Carried by the frame 11 is a mold which may include a relatively stationary mold section 29 and a relatively movable mold section 30. The latter may include one or more mold cavities 31 for molding one or more articles, which may be alike or different in design, the mold cavities be ing made to suit. The different mold sections 29 and 30 are so arranged that when the movable section moves into engagement with the sec- 'tion 29, the mold cavity is completely closed.

For mounting and operating the movable mold section 30, the same may be mounted on a plate element 32 that may be fixed to a head 33 carried by a bar 34 operated by a piston 35. The latter is reciprocable in a cylinder 36 mounted on the frame 11, and having a hub 37 in which said bar is longitudinally slidable. It will be noted that the parts 30, 32, 33 are reliably carried by the bar 34, with the parts 32, 33 moving in sliding contact with the plates 14, 15 of the frame, so that a powerful reenforcement is obtained, and parts 32, 33 prevented from turning.

Three expansion coil springs 38 are mounted in the cylinder so as to bear on the piston 35 for moving the same toward the left, until stopped by a hub 39 forming part of the element 33.

For causing the piston 35 to advance against the force of the springs 38, a fluid such as air or liquid may be supplied to the cylinder from any suitable source through a tube 40. The latter leads to a pasage 41 controlled by an intake valve 42. A similar passage 43 may be controlled by an outlet valve 44, an outlet tube 45 communicating with said passage 43. The valves 42, 44 operate in opposite directions, an expansion coil spring 45 taking around the stem 46 of valve 44 and bearing on collar 47 so as to tend to move the same into closed position. In'order to open frame 11, and the valve stem having its end portion slidably fitted at 5'7 in said bracket 56. For closing the valve 42, a cam 58 mounted on shaft 19 operates on a roller 59 of a lever 60, pivotally mounted at 61 on a lug 62 extending from adjacent bearing 18, and the lower end of said lever acting on the collar 55 so as to move the valve 42 toward the left. a

The relatively stationary mold section 29 may be mounted on a plate element 63 suitably fixed to the machine frame 11. For supplying a substantially liquid molding material such as molten metal to the mold cavities 31, a container 64 for the metal may be provided, to which heat may be supplied as by burners. To

this container is connected a tube 66 leading into a passage 67 from which extend a plurality of branch passages 68 in a block 69. These branch passages are controlled by a combined valve and measuring means which may include a slide 70 slidable between guides '71 and having seating engagement at 72 with the underside of the block 69 and with an upper face 73 of a feeding head 74 having passages 75 that are out of alinement with the outlets of branch passages 68. Parts of the passages 75 may be provided by means of replaceable sleeves 76 of special metal such as stainless or other alloy or high temperature steel which will not be attacked by the molten metal. The slide 70 has a plurality of openings 77 extending therethrough, whose capacity is accurately determined to be equal to the masses of the different articles to be molded. When the slide valve 70 is moved into a position where its openings 77 aline with branch passages 68, said openings become filled with molten metal, and upon further movement, the slide closes passages 68 and the openings 77 move into alinement with passages 75 to discharge their respective contents thereinto.

For reciprocating the valve element 70, the same may have an extension 78 connected by a link '79 with a lever 80 that is pivotally mounted at 81 on a lug 82 of the frame plate 14. Said lever 80 is oscillated by a bell crank lever 83 hav ing lost motion pivotal connection therewith at 84, and pivotally mounted at 85 of an arm 86 extending from the machine frame. This bell crank lever carries a roller 87 engageable with a cam 88 mbunted on the shaft 24. A tension coil spring .8311 is connected to the lever and to the arm 28 of the frame so as to tend to cause the valve slide 70 to be moved toward the left.

Each passage 75 communicates at its end with a transverse horizontal passage 89 extending through plate element 63 and mold section 29, and also therebeyond toward the right as shown in Fig. 2. Each passage is preferably so arranged as to be in substantially central relation to the mold cavity 31 with which it cooperates. In each passage 89, a piston 90 is slidable, the end of the piston being at the right of passage 75' to permit communication between vertical passage 75 and horizontal passage 89. Each piston 90 is slidable along the entire length of passage 89 to the front face of mold section 29 so as to fully expel the molten metal into the mold and at the same time to snugly close the passage 75. When the piston 90 is in fully advanced position, its end may form a uniform part of the face of mold section 29.

For actuating the pistons or feeders 90,'the same may be connected with individual ,power pistons 91 reciprocable in cylinders 92 provided in a block 93 secured to the frame 11. Connected to the pistons 91 are rods 94 extending outside of the cylinders through a closure plate 95 for the cylinders. Expansion coil springs 96 take around the rods 94 so as to bear on the plate 95 and on nuts '97 mounted on the rods, whereby these springs tend to move the pistons 91 toward the right to retract the pistons 90. It is noted that the latter may be of uniform diameter through a tube 98 and thence into a passage 99 controlled by an inlet valve 100. The fluid flowing past valve 100 enters a vertical passage 101- located between the cylinders 92, and whence leads a passage 102 into a cross passage 103 which communicates with the different cylinders 92 back of the pistons 91 for exerting pressure thereon to advance the same against the force of springs 96. When the pressure is to be relieved so that said springs can retract the pistons, an outlet valve 104 is opened. The manner in which valves and 104 are controlled will now be described.

Valve 100 is mounted on a stem 105 slidable in a closure bushing 106 for the passage 99, and acted upon by an expansion coil spring 107 bearing on a nut 108 on the end of the stem so as to tend to close the valve. For opening the valve, a lever 109 pivotally mounted at 110 on the machine frame bears upward on the end of the valve stem 105, said lever being actuated by a connecting rod 111 loosely connected thereto and slidable in a passage 112 in the block 93 between the cylinders 92. At its upper end, said rod 111 is loosely connected to a fork 113 of a lever 114 pivotally mounted at 115 on a machine frame portion 116, and having a roller 117 acted upon by a cam 118 mounted on shaft 24. Valve 104 is mounted on a stem 119 slidable through a bushing 120 that is set in a closure plate 121 for the outlet passage 122. An expansion coil spring 123 takes around the valve stem and bears on the valve so as to tend to close the same. Said stem 119 is loosely connected to a fork 124 of a lever 125 pivotally mounted at 126 on the frame element 116, said lever having a roller 127 acted on by a cam 128 rotated by the shaft 24 to open against the force of spring 123.

In order to cool the mold sections 29 and 30 so as to assure rapid solidification of the molten metal, each of the plate elements 32 and 63 may constitute a temperature controller or cooler, as shown in Fig. 5. Thus each of these elements may have a series of passages 129 intercommunieating with each other as at 130, for travel of the cooling medium over a path of maximum length. Each element may have an inlet 131 and an outlet 132 leading respectively to a. suitable source and a suitable drain. The connections for element 32 may be so arranged, as may be desirable, in order to permit movement thereof by the piston 35. The different mold sections may be secured to these elements in any suitable manner. In the case of element 63, the same is mounted by means of screws 133, and the mold section 29 secured thereto by screws 134.

One type 'of article which this machine is adapted to mold is shown in Figs. 8 and 9. This article 135 is intended to be used as an ornament and may be made, for example, of pewter. It may be constructed to function as a buckle, and hence may have a loop portion 136 and a hook 137. The article 135 is of one piece, and may have suitable ornamentation as shown at 138 and additional ornamentation on the front face thereof. It will be noted that the article may have a slight irregularity or projection 139 at its rear face in substantially central position, this being caused by the plunger 90, and allowing for any slight variations in the quantity of molten metal supplied to the mold. In order to mold the article 135, a special mold structure is necessary, which will now be described.

The mold section 29 may be horizontally split at 140 so as to provide an upper mold portion 141 which is vertically reciprocable along the plane of the main mold section 29. For this purpose, section 141 is connected by a link 142 snug engagement at 140 with the main mold section 29. The mold section 141 may have U shaped grooves 152 in its bottom edge seating face at 140. When the mold sections 29 and 141 are in engagement with each other as shown in Fig. 3, only the ends of each groove 152 are open. When the section 141 is raised, each groove is completely opened so that the loop 136 cast in the groove can be disengaged therefrom and the article 135 removed from the mold. Obviously the shape of grooves 152 may be made to suit the particular loop 136 desired. It will be noted that as the loop 136 extends from the rear face of the article 135, the mold section 29 need not be otherwise changed, the main body of the article being cast in the cavity 31 of the mold section 30. e The latter, secured by screws passing through holes 153, is independently removable to vary the article produced without changing the loop obtained.

In order to mold the hook 137, the mold section 29 may have recesses 154 corresponding to the different mold cavities. Cooperating with these recesses, a slide 155 may be provided set into a recess 156 in the face of the mold section 29. This slide which may be a narrow strip of metal, may be connected by a link 157 with a rod 158 slidable in a hub 159 of the frame, the end of the rod having a pin 160 engaged in a slot 161 of a lever 162 pivotally mounted at 163 on the lug 83b and having a roller 164 actuated by a cam 165 that is turned by shaft 24. A plate 166 may form a strap connected to the mold section 29 across the slide 155 so as to form a guide therefor. In the closed position of the slide shown, the grooves 154 open at their lower ends and otherwise closed by the slide, are adapted to form the hooks 137. For d sengaging the cast hooks, the slide 155 is withdrawn to the left into the hub 159 so as to fully open both grooves 154. Since the slide is quiie narrow it can readily enter the circular passage in the, hub. Tending to return the slide to the right is .a tension spring 167 interconnect ng the frame with the lever 162.

In order to eject the cast articles 135, a plurality of nozzles 168 are arranged to discharge air or other fluid downward and against the mold section 30. These nozzles are stationary and located above the path of movement of the mold section 30 and its supporting parts, and are connected by passages 169 with a tube 170 which leads to any suitable source of air pressure. This tube may be split to communicate with a passage 171 formed in a block 172 mounted on the machine frame. Transversely intersecting the passage 171 is a passage 173 in which is slidably fitted a valve 174 having an opening 175 movable into and out of registry with passage 171 upon movement of the valve. For controlling the valve a lever 176 may be pivotally mounted at 177 on an arm 178 of the block 1'72. This lever may have a roller 179 actuable by a cam 180 rotated by shaft 24. The valve 174 may have a slotted stem port. on 181 for engaging the lever in the slotthereof. An expansion coil spring 183 takes around a portion of the valve stem and bears upward on a shoulder 184 thereof, thereby tending to close the valve and to retain theroller in contact with the cam.

A single source of fluid pressure (not shown) may be provided for the ejecting means and for the different cylinders. If the pistons for the cylinders be arranged to move along vertical paths, they maymove in one direction by the action of gravity, and hence automatically.

The method of operation of the machine will now be described. The mold is first closed by movement of the mold section 30 against mold section 29, including the section 141, until the parallel meeting faces of these mold parts are in uniformly continuous contact, it being understood that mold section 141 is lowered and the element 155 is in its position at the right end of its path of travel, as shown in Fig. 3. The movement of mold section 30 is caused by the p'ston 35, and by suitably arranging the different cams, the above described condition of the mold is readily obtained. Now a quantity of molten metal flowing downward from container 64 enters measuring openings 77 in valve slide 70 and this movement may occur during or subsequent to the closing of the mold. Then the valve slide '70 is moved to cut off the passages 68 and to communicate with passages 75, whereby the metal measured in the openings 77 flows into said passages in advance of pistons 90 and is free to flow by gravity into the mold cavities 31. Since the passages 89 are in central relation to their respective cavities, part of the measured quantity of metal necessary to fill a mold cavity 31 including grooves 152 and 154 will remain in the passage until forced by the piston 90 completely into the mold. It will be noted that the piston acts with a yielding pressure, due to elasticity of the a'-.r driving the actuator piston 91, so that a degree of adjustment is obtainable in the event of a slight variation for any reason of the quantity of metal furnished to the mold. Generally speaking, this quantity is so accurately measured that the article produced is perfectly smooth and even. By reason of this method of molding, no long projections or gates are left on the article to be later broken off. By arranging-the piston feed means 90 centrally of the mold and at the rear mold section, any mark such as 139 that might be produced, whether a projection or depression, is at the back of the article and will not be visible at the edge of the article, and, moreover, the pressure feed of metal in the mold is perfectly uniform in all parts thereof so that the molding can occur with maximum speed. After the metal has solidified, the mold is opened by retraction of mold section 30, mold member 141 is raised and mold element 155 is retractedleftward. Now the nozzles 168 deliver jets which blow the articles out of the mold, to be received in any desired accumulator. By suitably arranging the cams hereinbefore described,

cams can be provided to accomplish this operation. However, it is preferable that the metal shall not be fed into passage '75 until the piston is retracted, since in this manner, the metal is kept at a maximum temperature and is subject to as little initial cooling as possible, whereby premature solidification in the passages is prevented.

In general the parts through which the metal flows are made of such material as not to be affected by the molten metal as by forming alloys therewith, and the different parts of such materials and with such clearances as not to cause binding due to expansion caused by heat. Various exposed parts such as 69 and 70 may be insulated, and the burners 65 may include flame jets directed upon the block 69 for assuring a'sufiiciently high temperature in the passages 68 and valve element 70. If the article is of sufficient size, the mass of metal flowing through the different passages may have sufficient heat in itself to keep them at the proper temperature. But if the article 135 is very small, additional heat may be necessary and hence the sleeves 76 may constitute electrical heating units which may be connected with a suitable control or rheostat having indicia 191 arranged to indicate in units corresponding to the mass of the article 135 to be produced. This control and the heating units may be connected by conductors 192 with a suitable source of current. In operation, the article 135 is weighed, and the control set according to that weight, thereby assuring a flow of current to the unit in inverse proportion to the mass of the article, so that the machine can be kept at the proper minimum temperature.

In Fig. 11 is shown a modification of the invention wherein the measuring means for the liquid metal is omitted, and the latter fed to the mold by any suitable means, as by gravity, a combined valve, gateway and shearer being provided .in cooperation with the mold cavity so that an article can be cast in an improved manner without requiring any subsequent breaking or removal of gates. Specifically, the mold may include a stationary replaceable mold section 193 and a movable mold section 194, the former having a mold cavity 195 and the latter acting as a closure therefor along the surface 196. These mold sections may have respective cooling units 193a and 194a. The stationary mold section may be supported in any suitable manner, while the movable mold section may be reciprocated by member 197 to open and close the mold. The upper faces of the molds may lie in a single plane such as 198, if desired, and it is a feature of this invention that the mold cavity has a part or wall in coincidence with said plane as shown at 199. Movable along the plane 198 in any desired path is a slide member 200 whose lower face may form a wall for the mold cavity. This slide may be guided asfor reciprocation at right angles to the plane 196, and may have one or more openings 201 extending therethrough movable in this manner into and out'of registry with the mold cavity 195. Above the slide member, and having sliding engagement with the upper surface of the latter at 2021s a stationary block 203 having an opening 204 extending therethrough that may be larger than opening or openings 201 so as to encompass the same, the latter being movable into and out of registry therewith. A long vertical tube 205 communicates with the opening 204 and with a container 206 for the molten metal. The reciprocatory mold section 194 may have a vertically movable section 208 similar to section 141.

A reciprocatory ejector member 207 may extend through openings in the movable section 208 for ejecting molded articles. Normally, the end of said ejector member coincides with an adjacent wall of the mold, so that the same is entirely smooth and uniform, and said member closes the said openings. The member 207 may be actuatedby a stationary ram 209, and other actuating means and heating and cooling means may be provided as hereinbefore described.

In operation, when the mold is closed, the slide member 200 acting as a gateway,moves into position so that opening 201 thereof is in registry with opening 204 and mold cavity 195 permitting a free flow of molten metal into the latter, which in that position of the device in eifect constitutes a part of the passage means for the molten metal. The molten metal enters the mold under the pressure of gravity as determined by the height of the tube 205. Then the slide member is moved, for example, toward the right so as to shear off the metal level with the top of the mold cavity, and acts as a valve for closing the opening 204 in the block 203. When the metal has solidified, the mold is opened, and the ejector 207 expels the cast articleupon upward movement of section 208 and the ejector therewith so that a hook or loop on the cast article is readily disengaged. The cycle of operations is now ready to be repeated. No metal will solidify in opening 201, since the slide member may be hot and may constitute a heating unit. Moreover, the quantity of metal in the opening 201 is so small as to be readily molten on contact with molten metal in opening 204. Since the opening 201 does not constitute a measuring means for molten metal, the same slide member can be used with different molds for casting articles of different masses. As

' the slide member may uniformly contact both mold sections 193, 194 at the plane 198, there is no possibility of leakage even though opening 201 should extend on opposite sides of the plane 196, although said opening may be wholly on one side of said plane for communication with mold cavity 195.

I claim:

1. A device including a mold having a plurality of mold sections, one of said sections having a mold cavity and being movable relatively to the second mold section so that the latter closes the mold cavity, a container for molten metal, a passage for conveying the molten metal from the container to the mold, said passage having one end thereof terminating in the second mold section so as to communicate with the mold cavity, a combined valve and measuring means in said passage for controlling and measuring the flow of metal through said passage, actuator means for moving the combined valve and measuring.

2. A device including a mold having a plurality of sections one of which is movable to close the mold, a container for molten metal, a passage intercommunicating the mold and the container, a

combined valve and measuring means for controlling the fiow of metal into the passage and for measuring the quantity of metal so entering the passage, said combined valve and measuring means including a slide member having a metal receiving opening movable into and out of registry with said passage, a piston means associated with the passage for creating pressure on the metal in the mold, and means for successively causing movement of the movable section for closing of the mold, movement of the combined valve and measuring means to feed metal into said passage, and movement of said piston for creating pressure on the metal in the mold.

3. A device including a mold having a plurality of sections one of which is movable to close the mold, a container for molten metal, means for supplying heat thereto, a passage intercommunicating the mold and container, a combined valve and measuring means for measuring the quantity of metal flowing into the passage, a piston means in the passage for expelling the metal into the mold and exerting pressure on the metal therein, actuatormeans for successively closing the mold, causing the measured quantity of metal to be supplied to the passage, and causing the piston means to operate and exert pressure on the metal in the mold, said actuator means opening said mold after the metal therein has solidified, and means for ejecting the article from the mold.

4. A device including a mold having a plurality of sections one of which is movable to close the mold, a container for molten metal, a passage intercommunicating the mold and the container, a combined valve and measuring means for controlling the flow of metal, into the passage and for measuring the quantity of metal so entering the passage, a piston means associated with the passage for creating pressure on the metal in the mold, and means for successively causing movement of the movable section for closing of the mold, movement of the combined valve and messuring means to feed metal into said passage, and movement of said piston for creating pressure on the metal in the mold, and heating means for imparting heat to said passage, said heating means including a control means arranged to increase the heat imparted to the passage by the heating means in inverse ratio according to the masses of metal to be measured by the combined valve and measuring means.

5. A device including a mold split along a plane and having a mold cavity openable along said plane, said mold having an external sur-= face for a valve and the mold cavity being in direct communication with the valve surface, a valve means movable along said surface and adapted to form a wall for the mold cavity, and means for gravitationally supplying material to the mold cavity, the valve means being so coordinated with the mold cavity and the material supplying means as to establish or cut off communication therebetween along said valve surface upon movement of the valve therealong.

6. A device including a mold having a mold cavity, the latter being openv at an external surface portion of the mold, said mold being split along a plane intersecting said surface of the mold so that said mold is openable, said opening of the mold cavity affording an intake for material, means for supplying material to the mold cavity through said intake thereof, and valve means movable along said surface portion to cut oif the supply of material thereto, said valve means straddling said plane and being adapted to constitute a wall for the mold.

7. A casting device including a mold having an open mold cavity, means spaced from the mold for supplying a liquid material to the mold cavity under gravity feed, and a member disposed between said mold and said means, said member I having a passage therethrough for' intercommunicating said mold cavity and said means, said member having slide valve surface engagement with each of the mold and means transversely of said passage and being movable along the valve surfaces for establishing and cutting cfi communication between the mold cavity and said means through said passage, whereby an article can be cast in the mold cavity without removable gate sections. 

